Retrieval devices may be used to remove material from within a subject's body. The material may include inorganic material, such as parts of a medical device or other foreign matter. The material may also include organic material, such as blood clots, tissue, or biological concretions such as urinary, biliary, and pancreatic stones. Biological concretions can develop in certain parts of the body, such as in the kidneys, pancreas, ureter, and gallbladder.
With conventional retrieval devices, in some instances material may be difficult for a user to capture with the device. For example, the material may be too large to fit through openings in the device. Or the material may be so small that it may slip through the openings in the device. It may also be difficult to keep material in the device when the user attempts to withdraw the material from the subject's body. For example, the material may be too large to be removed intact from a subject's body after it has been captured within the device. To release the material from the device, a user may attempt to dislodge the material from the device by maneuvering the device. If the material cannot be released from the device in that manner, the user may attempt to break the material into smaller pieces in the device using an emergency rescue handle. If the material doesn't break, the device may break along its drive wire. The subject may have to undergo surgery to have the broken device removed.